Domain Browsing Issue SBS 2003 server, XP Pro client

Hello Experts,

I am having a problem on and off browsing my AD shares.  I have searched and tried many fixes without success and would appreciate any help in resolving this.  The server is called srv1, SBS 2003 SP1, running DHCP, DNS, and WINS, IP address 192.168.1.2, the clients are XP Pro / Win2k Pro (I have seen the problem on all clients) and the box I'm using to work on this problem is called DELL-FH, XP Pro SP2, domain is MarketEthos.local

When the problem occurs:
1.  On the client, the Computer field in My Network Places says Unknown  (when it is working properly it says Srv1)
2.  On the client, Browstat status returns the following  (when it is working properly the output looks fine):

Browsing is active on domain.
Master name cannot be determined from GetAdapterStatus.  Using \\SRV1
Could not connect to registry, error = 53
Unable to determine build of master browser: 53
Unable to determine server information for browser master: 53
1 backup server retrieved from master SRV1
  \\SRV1
Unable to retrieve server list from SRV1: 53

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Recent client messages from event viewer as I've tried to fix it:

NETLOGON event 5719:

No Domain Controller is available for domain MARKETETHOS due to the following:
There are currently no logon servers available to service the logon request. .
Make sure that the computer is connected to the network and try again. If the problem persists, please contact your domain administrator.

DCOM event 10010:

The server {F3A614DC-ABE0-11D2-A441-00C04F795683} did not register with DCOM within the required timeout.

LSASRV event 40961:

The Security System could not establish a secured connection with the server cifs/srv1.marketethos.local.  No authentication protocol was available.

DnsApi event 11190:

The system failed to update and remove pointer (PTR) resource records (RRs) for network adapter
with settings:

   Adapter Name : {4549BD62-BE55-4169-9BE4-737E95215FC2}
   Host Name : DELL-FH
   Adapter-specific Domain Suffix : MarketEthos.Local
   DNS server list :
           192.168.1.2
   Sent update to server : <?>
   IP Address : 192.1.1.1

 The system could not remove these PTR RRs because of a security related problem. The cause of this could be that (a) your computer does not have permissions to remove and update the specific DNS domain name or IP addresses configured for this adapter, or (b) there might have been a problem negotiating valid credentials with the DNS server during the processing of the update request. For specific error code, see the record data displayed below.

AutoEnrollment event 15:

Automatic certificate enrollment for local system failed to contact the active directory (0x8007054b).  The specified domain either does not exist or could not be contacted.
  Enrollment will not be performed.

Userenv event 1054:

Windows cannot obtain the domain controller name for your computer network. (The specified domain either does not exist or could not be contacted. ). Group Policy processing aborted.

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Recent server messages received as I've tried to fix it:

NETLOGON event 5782

Dynamix registration or deregistration of one or more DNS records failed with the following error:
No DNS servers configured for local system.

WLBS event 35

NLB Cluster 0.0.0.0:  Cluster mode cannot be enabled due to parameter errors.  All traffic will be passed through to TCP/IP.  Restart cluster operations after fixing the problem by running "wlbs reload" followed by "wlbs start".

Kerberos event 4

The kerberos client received a KRB_AP_ERR_MODIFIED error from the server DELL-FH$.  The target name used was cifs/DELL-FH.MarketEthos.local.  This indicates that the password used to encrypt the kerberos service ticket is different than that on the target server.  Commonly, this is due to identically named machine accounts in the target realm (MARKETETHOS.LOCAL) and the client realm.  Please contact your system administrator.

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Netdiag on the server shows all tests passed except 3 skipped:  Trust relationship test, WAN configuration test (No active remote access connections), IP Security test.

Dcdiag on the server shows 1 test failed:

Starting test:  systemlog
An Error Event occurred.  Event ID: 0x40000004
Time Generated:  06/13/2005 09:14:56
Event string: The kerberos client received a
........................SRV1 failed test systemlog

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Thanks.